This anchor expands and wedges against solid walls of rock. And, once it is expanded, the harder the pull on the rod-the tighter it wedges. Wedges are made of ductile iron with a rust-resistant coating. Rod should be in line with the guy.More information on Wedge Style Rock Anchors
The Chance Grouted Rock Anchor is designed to be used in situations where the soil is too rocky to use screw anchors, but the rock is fractured preventing the use of wedge style rock anchors.